The present invention relates to a numerical control tape preparation machine wherein inherent data required for controlling an automatic insertion machine for inserting electronic parts into printed circuit boards are recorded by punching a tape.
In general, automatic insertion machines for inserting electronic parts (resistors, capacitors and so on) into printed circuit boards incorporate a numerical control system. In general numerical control data used with the automatic insertion machines include data of positions to be inserted and inherent data required for the control of an insertion machine such as data for selection of types of parts to be inserted and data for designating the insertion directions on a printed circuit board. Of these data, data concerning the insertion positions are obtained when a printed circuit board is designed. In practice, elongation and shrinkage after the step for punching apertures in printed circuit boards is not negligible. Therefore, the part insertion hole positions must be directly measured from a printed circuit board to be used, and dimensional data must be obtained in the form of X coordinate and Y coordinate.
So far a printed circuit board to be measured is set on an X-Y table with pulse motors of an automatic insertion machine; a numerical control device or the like incorporated within the insertion machine itself is operated so that object insertion apertures of the printed circuit board may be in coincidence with the centers of leading ends of an insertion head which are references; and the displacement data are obtained by reading with a counter a number of oscillation pulses of pulse motors. Based on thus obtained data, an operator operates keys on a typewriter coupled to a puncher available in the market so that tape is punched and a numerical control tape is prepared.
The above prior method has the following defects:
(1) In case of measurement of positioning data, the insertion machine must be temporarily stopped so that the rate of machine operation drops. PA1 (2) An operator must visually observe the degree of alignment between an insertion aperture of the printed circuit board and the leading end of the machine insertion head, thereby judging the positioning conditions. Therefore correct positioning is difficult so that data required for preparation of correct positioning tape cannot be obtained. PA1 (3) Reconfirmation of the positioning conditions with the positioning tape is difficult. In order to correct positioning data, a new punch tape must be provided again. PA1 (1) When the center position of a part insertion aperture is to be correctly aligned or positioned, with a projector type an image is not clear so that it is difficult to view a profile of the aperture. With a probe stylus type and a printed circuit board or the like, the latter is damaged. Furthermore workability is poor. PA1 (2) When a printed circuit board is mounted on the X-Y table, there is no relationship with a printed circuit board mounting system employed in the part insertion machine so that a numerical control tape as prepared cannot be used with the part insertion machine. PA1 (3) There is not provided a monitor which displays all of codes used in the program for the part insertion machine. Therefore prior to the punch-out or print-out of the prepared program, mistakes cannot be checked and corrected. PA1 (4) An operation unit for positioning a printed circuit board and peripheral data-out equipment such as a tape puncher, a tape reader, a printer and so on are independent of and separated from each other so that they cannot be simultaneously operated. As a consequence, operability is poor, and they are large in size and expensive.
Next the method consisting of the combination of a general coordinate reader employing an X-Y table and a typewriter type tape puncher device has the following problems:
Therefore this method is inconvenient to an electronic part automatic insertion machine which must prepare punch tapes very frequently in order to meet the change of one type printed circuit boards to another type and the change in insertion positions.